The present invention relates generally to communication networks. More particularly, and without limitation, the present invention is directed to an access control system, method, and arrangement that dynamically reallocates Location Area Identities (LAIs) in a wireless communication network providing home or small area coverage.
Some operators desire to provide home or small area Wideband Code Division Multiple Access (WCDMA) or Global System for Mobile communications (GSM) or Long Term Evolution (LTE)/System Architecture Evolution (SAE) coverage for a limited number of users utilizing a small radio base station (RBS), often referred to for example as a Femto RBS or a Home eNodeB. In the discussion herein, the term Home 3G Access Point (H3GAP) is utilized to refer to the Femto RBSs of the different technologies. The H3GAP provides normal WCDMA coverage for the end users and connects to a femto radio network controller (Femto RNC) using an IP-based transmission. This connection may be made with fixed broadband access such as xDSL, cable, and the like, or alternatively, wireless broadband access such as WiMAX may be utilized.
FIG. 1 is a simplified block diagram of an existing access network architecture 10 providing home or small area WCDMA coverage for a limited number of users utilizing a plurality of femto cells 11. Four femto cells are illustrated for exemplary purposes. The femto cells are overlain by two macro cells 12. The macro cells are controlled by macro RBSs 13. The RBSs connect to a radio network controller (RNC) 14 through an IP/ATM-based transmission 15. Each femto cell is controlled by an associated H3GAP 16. The H3GAPs connect to the RNC through IP-based transmissions 17. The RNC connects to a core network (CN) 18 through an Iu interface 19.
In some cases, the H3GAP may be equipped with a WCDMA receiver making it able to camp on WCDMA cells and read the relevant system information.
The existing network architecture has a number of limitations. First, since a Femto access network is built by the end user plugging in the H3GAP to the broadband connection, the system has to work in a plug-and-play fashion. Also, the number of Location Areas (LAs) is limited. A number of LAs may be allocated for the femto cells controlled by H3GAPs. These LAs are reused and allocated to the H3GAPs. There are only 65,000 LAs available per Public Land Mobile Network (PLMN), so each H3GAP cannot have its own LA. It should also be noted that if a large number of LAs are utilized, this places an extensive operations and maintenance burden on the core network. Therefore, a number of LAs (for example 100-1000) are selected and reused between the H3GAPs.
Another limitation of the existing architecture relates to access control. The access control function prohibits an unauthorized User Equipment (UE) from accessing and utilizing another end user's H3GAP and broadband connection. The rejection of an unauthorized UE may be indicated by a “Location area not allowed” message or a “No suitable cells in location area” reject cause during the Location Updating procedure. When a UE receives one of these messages, the UE stores the identity of the LA (the LAI) in a “forbidden LAIs” list. There may actually be two different forbidden LAIs lists: the “forbidden location areas for regional provision of service” and the “forbidden location areas for roaming”, but in either case, the UE retains the forbidden LAIs list until power down or until a predefined time period has expired (12 or 24 hours according to the 3GPP TS 24.008 specification). The UE does not attempt to access any LA on the forbidden LAIs list while the information is stored.
However, this aspect of access control may cause problems due to the reuse of LAs. For example, a given UE being rejected at another end user's H3GAP may have the same LA at its own H3GAP or at another H3GAP the UE is authorized to access. The rejection will cause the UE to store the associated LAI on the forbidden LAIs list. As long as the LAI of the UE's own H3GAP is in the forbidden LAIs list, the UE will not attempt to access its own H3GAP or other H3GAPs it is authorized to use, which have the same LAI.
Accordingly, there is a need for an access control system, method, and arrangement that overcomes the shortcomings of the prior art. The present invention provides such a system, method, and arrangement.